Previous methods have been reported in the literature for coating substrates with polymers to alter the chemical and physical properties of the substrate surface. In traditional colloidal chemistry, for example, polymers are coated onto nanoparticles by physisorption, thus providing a passivation layer and preventing the nanoparticles from aggregation or degradation. Polyelectrolyte deposition is a popular method due to the simplicity of the process. This method relies on the Coulombic attraction between a charged nanoparticle and an oppositely charged polyelectrolyte polymer. (Wang, D. et al., Chem. Mater. 2002, 14:1909-1913.) The drawback to this method is that it is limited only to polymers that are available in a polyelectrolyte form.
Alternatively, polymers can be coated onto substrates by covalent bond formation. Covalent attachment generally falls into one of two categories, the first of which is the so-called grafting-from method. (Bourgeat-Lami, E., J. Nanosci. Nanotech., 2002, 2:1-24.) In this approach, the polymer is produced in situ, which also is known as surface-initiated polymerization. (Bartholeme, C. et al., Macromolecules, 2003, 36:7946-7952.) Another common approach to covalently coating substrates with polymers is the grafting-to technique. This approach employs polymers that possess specific functional groups that can react with surface functionalities on the substrates. Again, the drawback to these methods is that they are limited to polymers that have specific functional groups or polymers that can polymerize in situ.
U.S. Pat. No. 5,830,539, which is incorporated herein by reference, describes embodiments of a method for altering the chemical and physical properties of the surface of a microstructure, e.g., a micro-well etched into a silicon wafer, by applying a thin film of a polymeric material to the microstructure surface. U.S. patent application Ser. No. 10/769,423, filed Jan. 30, 2004, which is incorporated herein by reference, describes embodiments of a method for preparing polymer-based microstructures, such as micro-wells and micro-towers, on substrates.
Of particular interest is the coating of substrates with biocompatible monomers or polymers. For example, carbohydrate-coated substrates can be used to study the interactions between carbohydrates and proteins. Carbohydrates also have a unique ability to specifically interact with receptors on pathogens and toxins. Carbohydrates are stable compounds and are inherently biocompatible, nontoxic and non-immunogenic. Thus, they are a useful tool in many applications, such as diagnostics, environmental monitoring, food safety control, and the detection and decontamination of biological pathogens and toxins.
For this reason, there is a need for new and robust methods for generating biocompatible surfaces. These biocompatible surfaces will find application in areas such as glycomics, carbohydrate-protein interactions, drug delivery, drug discovery, nanomedicine, improved biomedical devices, and pathogen and toxin sensing and decontamination.